Electronic camera

ABSTRACT

an electronic camera includes: an image-capturing unit that creates an image by capturing an image of a subject; an enlarged image generating unit that creates an enlarged image by enlarging a portion of the image created by the image-capturing unit; an optical viewfinder that enables verification of a subject range corresponding to a range of the image created by the image-capturing unit; and a warning output unit that issues a warning when the enlarged image generating unit is in operation.

INCORPORATION BY REFERENCE

The disclosure of the following priority application is hereinincorporated by reference:

Japanese Patent Application No. 10-58120, filed Mar. 10, 1998

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic camera having anelectronic zoom function whereby a portion of an image obtained bycapturing an image of a subject is displayed in an enlargement and anoptical viewfinder.

2. Description of the Related Art

There are single or fixed focus type electronic still cameras in theprior art that have a function of enlarging the central portion of animage created at an image-capturing element through image processing toobtain an image that appears as if it were photographed with a telephotolens. Hereafter, this function is referred to as “electronic zoom.”

It is to be noted that the enlarged image obtained through theelectronic zoom may be displayed on, for instance, a liquid crystaldisplay provided at the camera body of the electronic still camera.

In addition, some electronic still cameras that are provided with a zoomlens to perform optical zooming (hereafter referred to as “opticalzoom”) are also capable of achieving electronic zoom.

With such an electronic still camera, even when the zoom-in achievedthrough the optical zoom has reached its limit, for instance, an imagethat appears as if it were photographed at a focal length that is longerthan the actual focal length can be created by implementing a zoom-inthrough the electronic zoom.

FIGS. 5A and 5B illustrate the relationship between the zooming and thefocal length achieved through the optical zoom and the electronic zoom.In the figures, the “actual focal length” indicates the focal lengthdetermined through the optical zoom, whereas the “synthesized focallength” represents the focal length determined by combining the opticalzoom and the electronic zoom.

Normally, an electronic still camera capable of optical zoom is providedwith an optical zoom viewfinder at which the range of the subject withinthe viewfinder screen can be varied by moving the viewfinder lens.

However, since the range of the subject is changed in conformance to theactual focal length at the optical zoom viewfinder, the range of thesubject within the viewfinder screen cannot be changed if the zoom-inachieved through the optical zoom has reached its limit, as illustratedin FIG. 5A.

In addition, as illustrated in FIG. 5B, if a zoom-in is implementedthrough the electronic zoom while a zoom-in through the optical zoom isin progress, it is difficult to move the viewfinder lens in conformanceto the electronic zoom and, as a result, it is not possible to match therange of the subject within the viewfinder screen with the range of thesubject displayed on a liquid crystal display or the like.

Thus, there is a concern that when the photographer performsphotographing while monitoring the optical viewfinder, he may notrealize that the electronic zoom is set and he may press the releasebutton thinking erroneously that the image of the subject as seen in theviewfinder will be recorded.

In other words, there is a problem in that, in such a case, since therange of the subject, whose image is photographed while the electroniczoom is set, does not match the range of the subject within theviewfinder screen, an image that the photographer does not expect isrecorded.

It is to be noted that electronic still cameras having an opticalviewfinder (including an optical viewfinder without a zooming function)among the single focus type electronic still cameras described earlier,too, have a similar problem.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electronic cameracapable of reducing photographing errors occurring as a result of therange of the subject in the viewfinder screen not matching thephotographing range, and in particular, photographing errors resultingfrom the range of the subject in the viewfinder screen not matching therange of the subject displayed by a means for display.

In order to attain the above object, an electronic camera according tothe present invention comprises: an image-capturing unit that creates animage by capturing an image of a subject; an enlarged image generatingunit that creates an enlarged image by enlarging a portion of the imagecreated by the image-capturing unit; an optical viewfinder that enablesverification of a subject range corresponding to a range of the imagecreated by the image-capturing unit; and a warning output unit thatissues a warning when the enlarged image generating unit is inoperation.

Another electronic camera comprises: an image-capturing unit thatcreates an image by capturing an image of a subject; an enlarged imagegenerating unit that creates an enlarged image by enlarging a portion ofthe image created by the image-capturing unit; an optical viewfinderthat enables verification of a subject range corresponding to a range ofthe image created by the image-capturing unit; a display unit thatdisplays the image created by the image-capturing unit or the enlargedimage created by the enlarged image generating unit; a decision-makingunit that makes a decision as to whether or not the subject range withina viewfinder screen, which can be verified in the optical viewfinder,and a range of the subject displayed at the display unit match; and awarning output unit that issues a warning when the decision-making unithas decided that the subject range within the viewfinder screen and therange of the subject displayed at the display unit do not match.

In this case, preferably, the decision-making unit decides that thesubject range within the viewfinder screen and the range of the subjectdisplayed at the display unit do not match when the enlarged imagecreated by the enlarged image generating unit is displayed on thedisplay unit.

Also, preferably, the electronic camera further comprises amagnification power setting unit that accepts an external operationrelated to setting of a photographing magnification power at theimage-capturing unit or setting of a magnification power to be used whenthe enlarged image generating unit creates an enlarged image, and thedecision-making unit decides that the subject range in the viewfinderscreen and the range of the subject displayed at the display unit do notmatch when a magnification power setting for creating an enlarged imageis received via the magnification power setting unit.

In each of electronic cameras described above, preferably, the warningoutput unit issues a warning so that a photographer can be made awarethe warning while verifying the subject range through the opticalviewfinder. Also, preferably, the warning output unit implements displayof the warning near the optical viewfinder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of. an electronic still camera;

FIG. 2 shows an external view of the electronic still camera;

FIG. 3 is an operational flowchart of an embodiment;

FIGS. 4A and 4B present examples of indices for indicating the focallength states;

FIGS. 5A and 5B indicate the relationship between zooming and focallength; and

FIG. 6 shows an example of a liquid crystal display within the opticalviewfinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following is a detailed explanation of an embodiment of the presentinvention in reference to the drawings.

FIG. 1 is a functional block diagram of an electronic still cameraadopting the present invention.

FIG. 2 is an external view of the electronic still camera adopting thepresent invention.

In FIG. 1, a control unit 11 within an electronic still camera 10 isconnected to an image-capturing unit 13, an image processing unit 14, aliquid crystal display 15, a memory interface 16, an external operationinput unit 17, a warning lamp 18 and a viewfinder unit 19 via a controlbus 12.

In this embodiment, the external operation input unit 17 reads the“ON/OFF” state of a release button 20 and the setting status of a zoomswitch 21, both shown in FIG. 2 and reports the readings to the controlunit 11. It is to be noted that the focal length corresponding to thesetting status of the zoom switch 21 is reported to the image-capturingunit 13, the viewfinder unit 19 and the like via the control unit 11.

The image-capturing unit 13, which is provided with a photographic lensand an image-capturing element (not shown), captures the image of asubject to create an image by driving the photographic lens incorrespondence to the focal length indicated by the control unit 11.

The viewfinder unit 19, which is provided with a viewfinder lens (notshown), captures the image of the subject to create an image at theviewfinder screen by driving the viewfinder lens in correspondence tothe focal length indicated by the control unit 11.

It is to be noted that the image created at the image-capturing unit 13is provided to the image processing unit 14 to undergo the imageprocessing that is to be detailed later, and is also displayed on theliquid crystal display 15 or is recorded in a recording medium such as amemory device via the memory interface 16 if the release button 20 isturned “ON”. In addition, the image created at the viewfinder unit 19 isprovided to the photographer via a viewfinder window 22 illustrated inFIG. 2.

FIG. 3 is a flowchart of the operation achieved in the embodiment.

The following is an explanation of the operation achieved in theembodiment given in reference to FIGS. 1-3.

When the main power is turned on, the control unit 11 issuesinstructions to the image-capturing unit 13 to create an image bycapturing the image of the subject, and issues instructions to the imageprocessing unit 14 and the liquid crystal display 15 to perform monitordisplay of the subject.

In response to these instructions, the image-capturing unit 13 starts tocapture the image of the subject (FIG. 3, S1) and the image processingunit 14 performs image processing on the image created at theimage-capturing unit 13 such as A/D conversion and gamma correctionbefore providing the image to the liquid crystal display 15. In otherwords, the image created at the image-capturing unit 13 is displayed onthe monitor (FIG. 3, S2).

It is to be noted that while such processing is in progress, thecorresponding image is provided at the viewfinder screen and to thephotographer via the viewfinder window 22, as explained earlier.

The control unit 11 constantly watches or monitors the state of therelease button 20 and the setting status of the zoom switch 21 reportedby the external operation input unit 17 as explained earlier, to make adecision as to whether or not the zoom switch 21 has been operated (FIG.3, S3).

In addition, if it has been ascertained that the zoom switch 21 has beenoperated through such decision making, the control unit 11 makes adecision as to whether or not the electronic zoom is set (FIG. 3, S4).

It is to be noted that while various methods may be conceived for thephotographer to set the electronic zoom, the electronic zoom is assumedto be set when the “T” side (telephoto side) of the zoom switch 21 hasbeen pressed down for 2 seconds or more after the zoom-in through theoptical zoom achieved by the image-capturing unit 13 has reached itslimit, in this embodiment.

When it is ascertained at the control unit 11 that the electronic zoomis set, it decides that the range of the subject whose image isdisplayed on the monitor and the range of the subject in the viewfinderscreen do not match (FIG. 3, S5), and the warning lamp 18 is turned on(FIG. 3, S6).

In addition, the control unit 11 reports the setting status of the zoomswitch 21 reported by the external operation input unit 17 to the imageprocessing unit 14. Also, it issues instructions to the image processingunit 14 and the liquid crystal display 15 to perform monitor display ofan enlarged or magnified image through the electronic zoom.

In response to these instructions, the image processing unit 14 enlargesthe image created at the image-capturing unit 13 in correspondence tothe setting status of the zoom switch 21 and provides the enlarged imageto the liquid crystal display 15. Thus, through this processing, theelectronic zoom is implemented and the enlarged image is displayed onthe monitor (FIG. 3, S7).

Now, if the electronic zoom is not set in a state in which the zoomswitch 21 has been operated (FIG. 3, S4 NO), the control unit 11ascertains that the optical zoom is set, and implements the optical zoomthrough the image-capturing unit 13 (FIG. 3, S8) and repeats theprocessing in S2 and the subsequent steps in FIG. 3.

In addition, based upon the state of the release button 20 and thesetting status of the zoom switch 21 reported by the external operationinput unit 17, the control unit 11 makes a decision as to whether or notthe release button 20 has been turn on (FIG. 3, S9), and if it isascertained that the release button 20 has been turn on, it issuesinstructions to the image processing unit 14 and the memory interface 16to record the image. In response to these instructions, the image thatis displayed on the monitor undergoes compression processing at theimage processing unit 14 to be provided to the memory interface 16 whereit is recorded in a recording medium such as a memory device (FIG. 3,S10).

As explained above, in this embodiment, when the electronic zoom is setvia the zoom switch 21, an enlarged image is displayed on the liquidcrystal display 15 and the warning lamp 18 provided near the viewfinderwindow 22 becomes lit.

With this, the photographer is notified that the electronic zoom is inprogress and that the range of the subject within the viewfinder screenand the range of the subject displayed on the liquid crystal display 15do not match, with a high degree of reliability.

Consequently, even when the photographer is operating the zoom switch 21while monitoring the viewfinder window 22, he will be aware of the factthat the electronic zoom is in progress if the warning lamp 18 becomeslit so that he can verify the range of the subject by checking the imagethat is displayed on the liquid crystal display 15.

It is to be noted that while the electronic zoom is set when the zoom-inthrough the optical zoom has reached its limit in the embodiment, aseparate operating switch for switching between the optical zoom and theelectronic zoom may be provided (or an icon corresponding to a selectorswitch may be added in the operating screen in the case of an electronicstill camera capable of displaying an operating screen on the liquidcrystal display), to make it possible to set the electronic zoom evenwhile the optical zoom is in progress, as illustrated in FIG. 5B.

However, with an electronic still camera in which the electronic zoom isset in this manner, it is necessary to warn that the range of thesubject in the viewfinder screen does not match the range of the subjectwhose image is on monitor display even when the optical zoom is inprogress after the electronic zoom has been implemented.

In addition, while the warning lamp 18 is provided in the vicinity ofthe viewfinder window 22 to issue a warning that the range of thesubject within the viewfinder screen does not match the range of thesubject whose image is on monitor display in this embodiment, if thepresent invention is adopted in an electronic still camera provided witha liquid crystal focusing screen within the viewfinder unit, forinstance, a warning may be displayed on the focusing screen instead.

Now, while image processing is performed by the image processing unit 14on an image created at the image-capturing unit 13, an index thatindicates the focal length state, as illustrated in FIGS. 4A and 4B, forinstance, may be superimposed on the image.

To be more specific, while the optical zoom is in progress, the shadedarea is increased or reduced in response to the operation of the zoomswitch 21 by the photographer, as illustrated in FIG. 4A, whereas whenthe electronic zoom is in progress after the optical zoom has reachedits limit, an image with the shaded area blinking is superimposed.

It is to be noted that a warning that the range of the subject in theviewfinder screen does not match the range of the subject whose image ison monitor display may be issued by blinking a portion of, or theentirety of the index indicating the state of the focal length.

In addition, in the case of an electronic still camera in which theelectronic zoom is set when the zoom-in through the optical zoom hasreached its limit, as in the embodiment, the photographer may benotified that the electronic zoom is in progress instead of being issuedwith a warning, since, when the electronic zoom is in progress, therange of the subject within the viewfinder screen and the range of thesubject whose image is on monitor display never match.

Furthermore, while the decision-making as to whether or not the range ofthe subject whose image is on monitor display and the range of thesubject in the viewfinder screen match is implemented by making adecision as to whether or not the electronic zoom has been set via thezoom switch 21 in this embodiment, this decision making may beimplemented by making a decision as to whether or not an enlarged imageis on display.

For instance, the image processing unit 14 may decide that the range ofthe subject whose image is on monitor display and the range of thesubject in the viewfinder screen do not match and issue a warning, whenthe control unit 11 issues instructions to create an enlarged image tothe image processing unit. Moreover, an image that is equivalent to awarning display (e.g., a message such as “Electronic zoom inprogress!!”) may be superimposed on the enlarged image.

While the explanation is given above in reference to the embodiment byusing an electronic still camera as an example, the present invention isnot restricted to be adopted in an electronic still camera. Forinstance, the contents of the present invention may be adopted in avideo camera handling motion pictures. In other words, the presentinvention may be adopted in all types of electronic cameras providedwith both an optical viewfinder and an electronic zoom function.

While the explanation is given above in reference to the embodiment onthe warning issued through the warning lamp 18 or through display on theliquid crystal focusing screen, i.e., on an example in which the warningis visually recognized, it may be recognized by sound, such as with abuzzer.

In reference to the embodiment, the explanation is given above on anexample in which the warning is issued in regard to whether or not theelectronic zoom is set or in regard to the subject range of image onmonitor display and the subject range that can be seen via the opticalviewfinder not matching. When such a warning is issued, display may beimplemented to make it possible to ascertain the degree of enlargementor magnification achieved through the electronic zoom, as well. Forinstance, display that enables verification of the range over whichenlargement processing is being performed through the electronic zoommay be provided on the liquid crystal display within the opticalviewfinder. FIG. 6 shows an example of such a liquid crystal displaywithin the optical viewfinder. A frame 24, 25 or 26 that indicates thesubject range in which the electronic zoom is being performed may besuperimposed on liquid crystal display or the like within a subjectrange 23 seen through the viewfinder window 22. When the frame 25 isdisplayed, for instance, the subject range corresponding to the frame 25is enlarged through the electronic zoom. In addition, when the frame 26among the frames 24, 25 and 26 is displayed, the power of magnificationor the factor of enlargement achieved by the electronic zoom is at itsmaximum.

1. An electronic camera comprising: an image-capturing unit that createsan image by capturing an image of a subject; an enlarged imagegenerating unit that creates an enlarged image by enlarging a portion ofthe image created by said image-capturing unit; an optical viewfinderthat enables verification of a subject range corresponding to a range ofthe image created by said image-capturing unit; and a warning outputunit that issues a warning when said enlarged image generating unit isin operation.
 2. An electronic camera according to claim 1, wherein:said warning output unit issues a warning so that a photographer can bemade aware of the warning while verifying the subject range through saidoptical viewfinder.
 3. An electronic camera according to claim 2,wherein: said warning output unit implements display of the warning nearsaid optical viewfinder.
 4. An electronic camera comprising: animage-capturing unit that creates an image by capturing an image of asubject; an enlarged image generating unit that creates an enlargedimage by enlarging a portion of the image created by saidimage-capturing unit; an optical viewfinder that enables verification ofa subject range corresponding to a range of the image created by saidimage-capturing unit; a display unit that displays the image created bysaid image-capturing unit or the enlarged image created by said enlargedimage generating unit; a decision-making unit that makes a decision asto whether or not the subject range within a viewfinder screen, whichcan be verified in said optical viewfinder, and a range of the subjectdisplayed at said display unit match; and a warning output unit thatissues a warning when said decision-making unit has decided that thesubject range within said viewfinder screen and the range of the subjectdisplayed at said display unit do not match.
 5. An electronic cameraaccording to claim 4, wherein: said decision-making unit decides thatthe subject range within said viewfinder screen and the range of thesubject displayed at said display unit do not match when the enlargedimage created by said enlarged image generating unit is displayed onsaid display unit.
 6. An electronic camera according to claim 4, furthercomprising: a magnification power setting unit that accepts an externaloperation related to setting of a photographing magnification power atsaid image-capturing unit or setting of a magnification power to be usedwhen said enlarged image generating unit creates an enlarged image,wherein: said decision-making unit decides that the subject range insaid viewfinder screen and the range of the subject displayed at saiddisplay unit do not match when a magnification power setting forcreating an enlarged image is received via said magnification powersetting unit.
 7. An electronic camera according to claim 4, wherein:said warning output unit issues a warning so that a photographer can bemade aware the warning while verifying the subject range through saidoptical viewfinder.
 8. An electronic camera according to claim 7,wherein: said warning output unit implements display of the warning nearsaid optical viewfinder.